Felimare villafranca is a species of colourful sea slug or dorid nudibranch, a marine gastropod mollusc in the family Chromodorididae.
This species is predominantly dark blue in colour with a pattern of longitudinal yellow lines. The yellow lines branch and curve, sometimes forming a network in the middle of the back. At the edge of the mantle there is a double yellow line with a series of bright blue elongate patches or a broken blue line between it and the next set of lines which cover the back. A series of white patches may be positioned inside these blue markings. The rhinophores are translucent blue with opaque white pigment at the base of the club and in a line on the back; the tips are blue. The gills are also translucent blue with a midline of opaque white on the inner and outer faces. The body grows to a length of 40 mm.